knna

{moderator note: the following posts 1-8 were originally posted in the SPD thread, but were split to this new thread thread in order to keep the data analysis separate from the data collection}

Hey!, very nice thread.

I want to contribute with a tool i developed to compare bulbs for growing.

It includes some spectrums.The way i digitalized spectrums is copying the spectrum to Paint(MS), zoom and put square mode (control+M), and use resize tool to adjust each square to 1, or 5, or 10nm. It would be a good idea if u do the same with the SPD of ur interest, and report it here.

Its an Excel table (i did it with Sun Open Office). U must introduce the output at each wavelenght (or 5 or 10nm band, depending of SPD resolution). Then, introduce the power of the bulb and the system (bulb+ballast) (if u dont know it, use the nominal watage), and the lm output (in Klm, u must divide lm by 1000).

The sheet provides info about bulbs photosyntetic action, but gives some valuable data about other concepts (red/blue ratio, total blue light emitted, near and far red output...).

Finally, the sheet report the bulbs efficiency, total micromols of photons emitted and their PUR (Photosyntetically Usable Radiation) value. Then, compute each PPF and PUR value per system watt (the most relevant data) and per Klm.

Obviously, the sheet refers to bulbs radiant power, and dont analize the way its emitted, but the PUR/Klm ratio permits to use lux data, about effective irradiation (ignoring the slight change in spectrum by the differential reflectance of reflectors and walls at each wavelenght, usually shifting to blue, as well by blues higher penetration power).

The main difficult issue when i was doing the sheet was what "photosyntesis action curve" use. Finally, i built one, details in this thread. I choosed join a generic action spectrum with cannabis spectrum absorbance.

Of course, there is an error margin in the results, because SPD graphs arent a accurate font, and the quantum yield curve is an aproximation. And all depends of how much accurate is the lm rating. I trust mayor brands lm data, but take horticultural brands lm data with a grain of salt.

Enjoy it, introduce ur prefered bulbs spectrum and improve the whole sheet freely.

Attached Files

	BulbsComp.zip (104.9 KB, 526 views)
	Plantillas.zip (16.0 KB, 214 views)

knna

If u want to show images inpost, upload it as attachment, and link it (insert image, copy the attachment URL).

This is the Floura analisis of my sheet:


As reference, u will need from 150 to 300 PUR in veg state per m2. Average 200-250. With 3 18w tubes, u get 9,431 *3=28,29PUR.

28,29/200=0,14m2 (1 1/2 sq ft) is the grow space allowed for that light (using decent reflectors).

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threeb

Gee, thanks Knna!

I already had downloaded your excel file from which i couldn't understand anything but now i think i get it.

So to sumarise if possible,
a. You need to cover the most possible spectrum of light needed by your plant to veg
b. You need an average of 200-250 PUR/m2 for ... intensity(?)

Off with lumens/wattage ?

I think this thread is breaking this down quite well...

btw by googling i find the aquarium scene about 10 times more informative on lighting data, these people are way ahead.
Lighting theory explained (it's focused on corals but gives a nice tutorial on the basics)

knna

Yes, i found many interesting info in acuaria webs, wich i used in the sheet.

Its difficult to know what wavelenghts plants need. Now im experimenting with leds, trying to know more (by trial/error). Are green light necessary? Although isnt strictly necessary, it improve yield? Same cuestion for far red light. Inavoidable for long day flowering plants, its necessary for a short day specie like cannabis?Improve yield?What percentages of each wavelenght are the best?

Until these questions will be answered, a reasonable choice is give plants all the spectrum, but putting emphasis in red light, with the higher photosyntesis promotion capacity, and provide enough blue light to ensure a health grow.

How much blue light is needed? Ive seen botany studies wich suggest there is absolute needings of blue light, rather than a percentage of irradiance. 35-40 microE/sec of blue light seems to be enough, and mantain internodal distances short (because of that, i included the total blue output in the sheet).

The good thing about the sheet (sure it can be improved with more people working in it) is we have a tool to know what are we giving to our plants, and we can compare with more knowledge.


PUR is a measure of PAR (in microE), corrected by absorbance and photosyntesis action spectrum. A little more accurate than only PPF (PAR in microE). And far more informative than lm or Watts. The main objetive is give up those ambiguous units. Lm isnt accurate because depend of SPD, and only is valid when talking about same or very similar SPDs. Watts isnt a good unit because depend of the bulbs eff (u need 800w of 20w CFLs to put the same microE than a 400w HPS).

PUR is the unit we must know properly. For reference, i use the standars we use usually: a 400w HPS per m2 is the min recomended. The 400w HPS bulbs rated are from 400 to 500 PUR. So, i take 400PUR as the min recomended per m2 in flowering, and the 400-800 range as the recomended. Depending of how much grow we want in veg, i take the 150-300PUR in veg (200-250 average).

PS: when no specified, units references are per sq meter

knna

As i said in my first post, the sheet refers to radiance, but i suggested it can be applied to irradiance, wich is what we want to know.

Ill explain how to do it. First, we need a luxometer or photometer to measure lux (sorry, at the moment, i dont use footcd). Then, we need to convert it to PPFD.

The conversion factor is obtained from PPF/klm data. We need to convert lux to PPFD, so we need lm/PPF conversion factor. Divide PPF/klm by 1000 (to correct to lm), and obtain the inverse (1/x). That is the conversion factor. Divide lux reading for it and u obtain the PPFD value (same process is valid to PUR).

Example: You are using Fluora lighting. Its PPF/klm value is 24,618.
Divide it by 1000=0,024618
Obtain 1/x =40,62 wich is the conversion factor.

If u had a lux reading of 4000lux, divide it by 40,62 =98,47 microE/sec reaching the plant.

Another example: a pure HPS, like Phillips SonT Plus. Its PPF/klm value=12,27 /1000=0,01227 1/x=81,5 conversion factor
20000lux=245,4 microE
40000lux=490,8 microE
80000lux=981,6 microE
To reach the saturation point (i use the similar tomato, about 1200microE)
1200microE *81,5=97800lux si the max light density with this bulb.

I upload a pic of a botany study, wich estimates the conversion factor from lux to PPFD of various light sources. A generic HPS with a 1/8" plexiglas barrier have a conversion factor of 83. So i think the sheet have a reasonable error margin.

PS: Ive notice its the same multiply lux readings by PPF/klm /1000. But the 1/x value remains more significant to us, mere mortals.

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knna

Any comments?

Nobody is interested in the sheet?

All days are many post asking about questions answered more accurately with this sheet than any other way, and nobody are interested in it?

retired?

This is fascinating and thank you for posting it kanna. I am still digesting the information. This look complex and a its going to take a minute to get into perspective. I have saved them for further investigation. If I have question and I'm sure I will, I will PM you.

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Newest grow room

knna

Ive expected some feedback for the sheet . If u dont understand something, ask and ill explain it.

I would like at less talk about the results, so im going to post pics of some results.








Enjoy

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Bulb Analyzer Tool

knna

I find the Plantastar specs, and the sheet results are very close

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Bulb Analyzer Tool

Quantrill

Hey knna, I am trying to get a grasp on this spreedsheet you have put together. Could you lookover this attempt of mine to input the hortilux super HPS data into it?


edit, I redid it with more accurite data, I think. The SPD graph they give is not very precise. When I enlarge it and put the grid over it, I find that their increments are not even. I mean there is 18 dots between 0 and 10 and 16 dots between 10-20 on the y axis., they vary as much as 4 dots between certain increments. Between 0-100 there are 180 dots, in my measurements I used 2 dots as 1 percent of reletive power. I should probably redo it with .555555 as the multiplier. So my numbers are cetainly skewed a bit.


Am I even inputting the proper data?

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Attached Files

	Hortilux EYE super HPS.zip (17.8 KB, 36 views)
	Copy of Hortilux EYE super HPS, better data.zip (17.6 KB, 90 views)

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